1. Field of the Invention
The present invention relates generally to cellular telephone and optical mouse technology and, more particularly, to a cellular telephone having an integrated, optically-based means for measuring the movement of the telephone across an underlying surface and an integrated, wireless means for communicating such relative displacement to a computer.
2. Description of the Related Art
Various cellular telephones having integrated camera functions are commercially available. Such telephones typically employ an camera unit including an image sensor, a multiple element fixed-focus lens assembly that is optimized for imaging subjects located at least 100 mm from the lens assembly, and a lens barrel for positioning the elements of the lens assembly over the image sensor. The image sensor is typically a CMOS image sensor or a CCD image sensor, depending upon the design goals for camera functionality, e.g., low-light performance and image noise floor. State of the art telephones may substitute a variable-focus camera unit that can be switched between a normal mode and a “macro mode” optimized for imaging subjects located at least 20 mm from the lens assembly. The image sensors in basic telephone designs typically provide a VGA-equivalent resolution of 640 by 480 pixels, but state of the art telephone designs may incorporate image sensors providing UXGA or even QXGA-equivalent resolutions, i.e., 1600 by 1200 or 2048 by 1536 pixels. In most telephone designs, the camera function can also assemble a series of still images to construct a movie sequence with a frame rate of 10-30 frames per second, and camera function is operatively coupled to a supplemental source of illumination, such as a xenon flash, to permit the imaging of subjects under low-light conditions. In certain state of the art telephone designs, the telephone can be wirelessly interfaced with a computer through various RF communications technologies such as Bluetooth® to provide remote data communications and/or file transfer capabilities.
Various mice employing optical motion-sensing technology are also commercially available. Such mice typically combine an image sensor, a source of illumination, a digital signal processor, and a peripheral interface as a means for translating observed motion over an underlying surface, such as a desktop, into measurements of relative displacement which are communicated to a computer and computer operating system for use in manipulating a command element. The optical sensor typically employs a CMOS image sensor shielded by a single lens element/cover that is optimized for imaging a portion of the underlying surface located 5-10 mm below the sensor. The source of illumination, which is typically a light emitting diode (LED) or laser diode (LD), is offset from the image sensor and oriented so that light is emitted toward a surface below the optical sensor, scattered off the underlying surface, and collected in photosites in the image sensor. The digital signal processor is programmed to sample the image sensor at a comparatively high frame rate, on the order of 1500 to 6500 frames per second, and to track the apparent movement of microscopic features of the surface between successive frames to determine the relative displacement of the mouse. This relative displacement is subsequently communicated to the peripheral interface, to a computer, and to computer operating system as an input for controlling a command element such as a cursor. These image sensors typically have a resolution of between 16 by 16 and 30 by 30 pixels, although other resolutions of comparable magnitude may be found in sensors marketed by various manufacturers. In certain state of the art mouse designs, the mouse can be wirelessly interfaced with a computer through various RF communications technologies such as Bluetooth® to control a command element such as a GUI cursor.
Camera phones and optical mice have become ubiquitous in business environments, but each is sold and used as a stand-alone device in accord with its intended function. However, and particularly in business travel situations, such a multiplicity of devices contributes to a number of problems, including the need to pack each device, the need to manage the cables associated with wired devices, the need to periodically recharge multiple wireless devices, etc. Moreover, mouse replacements such as laptop touch pads tend to be poor substitutes for mice, as they typically require a user to position themselves in front of the computer and behind the computer screen, so that a user making a presentation to an audience is at least partially obscured from their audience by a prominent barrier. Other mouse replacements such as remote presentation controls tend to be single function devices, providing a limited ability to control presentation software, but not the ability to fully control a command element such as a GUI cursor. Hence, it would be advantageous for certain users, such as business travelers, to combine certain existing cellular phone features with new optical, illuminating, and programming features to produce a cellular telephone having integrated wireless mouse functionality. Such an improved cellular telephone would permit a computer user to control a computer presentation without carrying a separate special purpose device, to avoid the need to manage an additional cable or battery-operated wireless device, and to avoid diminishing the effectiveness of a presentation by resort to a computer-integrated mouse replacement or limited function remote. Such an improved cellular telephone could also substitute for a mouse in situations where a computer user is away from their desk and/or laptop docking station.